title: A new MRI rating scale for progressive supranuclear palsy and multiple system atrophy: validity and reliability.
abstract: OBJECTIVE
  To evaluate a standardised MRI acquisition protocol and a new image rating scale for disease severity in patients with progressive supranuclear palsy (PSP) and multiple systems atrophy (MSA) in a large multicentre study.
  
  
  METHODS
  The MRI protocol consisted of two-dimensional sagittal and axial T1, axial PD, and axial and coronal T2 weighted acquisitions. The 32 item ordinal scale evaluated abnormalities within the basal ganglia and posterior fossa, blind to diagnosis. Among 760 patients in the study population (PSP = 362, MSA = 398), 627 had per protocol images (PSP = 297, MSA = 330). Intra-rater (n = 60) and inter-rater (n = 555) reliability were assessed through Cohen's statistic, and scale structure through principal component analysis (PCA) (n = 441). Internal consistency and reliability were checked. Discriminant and predictive validity of extracted factors and total scores were tested for disease severity as per clinical diagnosis.
  
  
  RESULTS
  Intra-rater and inter-rater reliability were acceptable for 25 (78%) of the items scored (≥ 0.41). PCA revealed four meaningful clusters of covarying parameters (factor (F) F1: brainstem and cerebellum; F2: midbrain; F3: putamen; F4: other basal ganglia) with good to excellent internal consistency (Cronbach α 0.75-0.93) and moderate to excellent reliability (intraclass coefficient: F1: 0.92; F2: 0.79; F3: 0.71; F4: 0.49). The total score significantly discriminated for disease severity or diagnosis; factorial scores differentially discriminated for disease severity according to diagnosis (PSP: F1-F2; MSA: F2-F3). The total score was significantly related to survival in PSP (p<0.0007) or MSA (p<0.0005), indicating good predictive validity.
  
  
  CONCLUSIONS
  The scale is suitable for use in the context of multicentre studies and can reliably and consistently measure MRI abnormalities in PSP and MSA. Clinical Trial Registration Number The study protocol was filed in the open clinical trial registry (http://www.clinicaltrials.gov) with ID No NCT00211224.
authors.affiliation: Brighton and Sussex Medical School, Trafford Centre for Biomedical Research University of Sussex, Falmer, East Sussex.
authors.forename: Yan
authors.initials: Y
authors.lastname: Rolland
authors.forename: Marc
authors.initials: M
authors.lastname: Vérin
authors.forename: Christine A
authors.initials: CA
authors.lastname: Payan
authors.forename: Simon
authors.initials: S
authors.lastname: Duchesne
authors.forename: Eduard
authors.initials: E
authors.lastname: Kraft
authors.forename: Till K
authors.initials: TK
authors.lastname: Hauser
authors.forename: Josef
authors.initials: J
authors.lastname: Jarosz
authors.forename: Neil
authors.initials: N
authors.lastname: Deasy
authors.forename: Luc
authors.initials: L
authors.lastname: Defevbre
authors.forename: Christine
authors.initials: C
authors.lastname: Delmaire
authors.forename: Didier
authors.initials: D
authors.lastname: Dormont
authors.forename: Albert C
authors.initials: AC
authors.lastname: Ludolph
authors.forename: Gilbert
authors.initials: G
authors.lastname: Bensimon
authors.forename: P Nigel
authors.initials: PN
authors.lastname: Leigh
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001479:Basal Ganglia / Q000473:pathology; D001921:Brain / Q000473:pathology; D002531:Cerebellum / Q000473:pathology; D016000:Cluster Analysis; D003388:Cranial Fossa, Posterior / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000473:pathology; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000473:pathology*; D009460:Neurologic Examination; D015588:Observer Variation; D011149:Pons / Q000473:pathology; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D012959:Socioeconomic Factors; D013494:Supranuclear Palsy, Progressive / Q000473:pathology*